The preventive measures of precision casting blowholes, I hope everyone can read carefully:
- 1. For complex thin-walled castings, in order to improve the air permeability of the precision casting shell, if possible, an exhaust hole can be set at the highest point. -) Reasonably set up the pouring system to prevent pouring entrainment and facilitate the discharge of gas in the cavity.
- 2. Properly increase the pouring temperature, reduce the distance between the ladle nozzle and the pouring cup as much as possible, reduce the pouring speed, so that the molten metal can be filled smoothly, prevent the gas from being involved, and make the gas in the cavity and the liquid metal can be discharged smoothly.
- 3. When dewaxing, the mold material should be cleaned out, and the residual mold material should be as little as possible.
- 4. The molding shell should be fully baked and the temperature should be high enough; the silica sol and ethyl silicate shells should be 950～1100 degrees Celsius, and the water glass mold shells should be 850～900 degrees Celsius. The heat preservation time is longer than &, to ensure the precision casting mold shell Roasted thoroughly, and gas-producing substances are fully eliminated. The completely roasted shell is white or light gray, and there should be no black spots.